Hello, Beijing: American Airlines to put Boeing 787 on its first international route

This is puzzling as to why they reduce seating capacity. Are the cost savings that much on the 787. Of course they don't tell what % of those seats were filled.
As configured by American, the 787 has 226 seats, compared to at least 247 seats on the 777-200. We say “at least,” because American is in the process of converting its 777-200 fleet. It is taking out the first-class section and installing its new design lie-flat seats in an expanded business class.

"As a result, there’s an interim configuration of 260 seats and an eventual configuration of 289 seats for the 777-200 fleet.